/*
 * Copyright 2012 Sebastian Annies, Hamburg
 *
 * Licensed under the Apache License, Version 2.0 (the License);
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an AS IS BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.googlecode.mp4parser.util;

import java.io.EOFException;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.ByteChannel;

/**
 * Creates a <code>ReadableByteChannel</code> that is backed by a <code>ByteBuffer</code>.
 */
public class ByteBufferByteChannel implements ByteChannel {
  ByteBuffer byteBuffer;

  public ByteBufferByteChannel(ByteBuffer byteBuffer) {
    this.byteBuffer = byteBuffer;
  }

  public int read(ByteBuffer dst) throws IOException {
    byte[] b = dst.array();
    int r = dst.remaining();
    if (byteBuffer.remaining() >= r) {
      byteBuffer.get(b, dst.position(), r);
      return r;
    } else {
      throw new EOFException("Reading beyond end of stream");
    }
  }

  public boolean isOpen() {
    return true;
  }

  public void close() throws IOException {
  }

  public int write(ByteBuffer src) throws IOException {
    int r = src.remaining();
    byteBuffer.put(src);
    return r;
  }
}
